High-intensity line-source lasers can be utilized to deliver energy selectively to clear thermochromic inks. Thermochromic inks or dyes are temperature sensitive compounds that can temporarily (or in this case permanently) change color with exposure to heat. Such thermochromic inks can, for example, change from clear to black at a given energy level. Digitally selective heating of the inks with, for example, a LIM (Laser Imaging Module) can deliver a digital image on a surface pre-coated with the thermochromatic inks.
The digitally selective switching of the laser power in the LIM can be enabled using a DMD (Digital Micro-mirror Device), which resides in the enclosure also containing the laser source (e.g., Laser Diode Array). DMD's are commercially available components, which were originally designed to operate with lower incident energy levels. The current level of incident energy, however, exceeds the device's ability to adequately dissipate heat from the DMD chip. If the DMD chip (and its internal components) exceed a critical temperature (70° C.), they can become damaged. Currently, a DMD can only run at about 80% power for a duration of approximately 20 seconds before attaining a maximum temperature. The desire is to have the ability to operate the device at 100% power @ 100% duty-cycle. However, a laser source such as a laser diode array uses a large amount of power and cannot be power-cycled at high rates of speed.